Infrared (IR) temperature sensors can monitor infrared light which is then converted into an electrical signal and ultimately to a temperature reading. The spectrum of infrared radiation cannot be readily seen by humans without the use of specially designed equipment that makes the spectrum visible. Measurement of infrared waves is calibrated in microns, ranging from 0.7 to 1000 microns. Today, infrared temperature sensors can be used to measure temperature of almost any type of moving part or object, including many used related to vehicles.
One of the most basic IR temperature sensor designs consists of a lens that focuses IR energy onto to a detector. The detector can convert the measured energy to an electrical signal, which can be displayed in units of temperature. An object's emissivity is used together with the captured energy in order to convert measured energy into temperature. Today, more sophisticated sensors can passively compensate for ambient temperature variations so as to effect accurate measurement of a target object.
One very useful feature of IR sensors is the ability to measure temperatures, e.g., without physical contact. This temperature monitoring ability is especially useful in situations where objects are in motion, e.g., in vehicular applications. Unfortunately, environmental effects upon the sensor require protective housings and the like to be installed to protect the sensors from environmental elements. Protective housings and the like include materials that vary in temperature and contribute to the IR energy path of the sensor thereby making accurate and efficient temperature measurements difficult.
With regard to conventional IR temperature sensors, significant measurement errors often occur when the IR sensor, e.g., thermopile, is subject to thermal conditions such as a wide range in operating temperatures, temperature rate of change, or static thermal gradients in the sensing region or path. Any IR visible object in the path between the sensing component and the measurement target will both deliver energy to the sensor as well as block a portion of the thermal energy emitted by object target; resulting in accurate and inefficient temperature measurement.